Sensei to Himitsu

Sensei to Himitsu summary:

Chapter 1-2 & Extra: Kaji's woken up from his nap hearing popular Tsunoda sensei getting hot and heavy with another guy! But it's his partner, the plain Aritou sensei that Kaji can't stop thinking about. Kaji's eyes are being opened as he finds that the needs and dark desires that can bind together lovers aren't always about love... Chapter 3-6: An assistant proffessor of agriculture quits his collage due to budget cuts. When looking for a new place to conduct his reasearch, he meets a boy willing to help him with his experiments what ever it may entail.